<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .button {
            width: 100px;
            height: 50px;
            background-color: blue;
            background-image: radial-gradient(circle 50px at top center,rgba(255,255,255,.8),transparent);
            border-radius: 12px;
            text-align: center;
            line-height: 50px;
            color: #fff;
        }
    </style>
</head>
<body>
    <div class="button">发光按钮</div>
</body>
</html>
